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CVE-2026-68166 (GCVE-0-2026-68166)

Vulnerability from cvelistv5 – Published: 2026-08-10 11:59 – Updated: 2026-08-23 12:46
VLAI
Title
userfaultfd: prevent registration of special VMAs
Summary
In the Linux kernel, the following vulnerability has been resolved: userfaultfd: prevent registration of special VMAs Vova Tokarev says: userfaultfd allows registration on shadow stack VMAs. With userfaultfd access, you can register on the shadow stack, discard a page ... and inject a page with chosen return addresses via UFFDIO_COPY. Update vma_can_userfault() to reject VM_SHADOW_STACK. While on it, also reject VM_SPECIAL so that if a driver would implement vm_uffd_ops, it wouldn't be possible to register special VMAs with userfaultfd. Since VM_SPECIAL includes VM_DONTEXPAND which is set but hugetlb, exclude hugetlb VMAs from the check for VM_SPECIAL.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 54007f818206dc27309ca423df4c87dd160a7208 , < d974b4b786214883bd8e56bda10b454c80fd6205 (git)
Affected: 54007f818206dc27309ca423df4c87dd160a7208 , < 495a28d5a100be1b232633f4c2dcc42ba10b3796 (git)
Affected: 54007f818206dc27309ca423df4c87dd160a7208 , < 165613191ad9d034bf17c00e3a142f9561597ec5 (git)
Affected: 54007f818206dc27309ca423df4c87dd160a7208 , < 0c26202b157f1efc3cd2f26f5c30f59b508a6a5d (git)
Affected: 54007f818206dc27309ca423df4c87dd160a7208 , < 3c58f641e813c3c71039f8fd4d4e2a3aab713288 (git)
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Linux Linux Affected: 6.6
Unaffected: 0 , < 6.6 (semver)
Unaffected: 6.6.153 , ≤ 6.6.* (semver)
Unaffected: 6.12.105 , ≤ 6.12.* (semver)
Unaffected: 6.18.44 , ≤ 6.18.* (semver)
Unaffected: 7.1.6 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
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    "datePublished": "2026-08-10T11:59:34.576Z",
    "dateReserved": "2026-07-30T09:28:09.372Z",
    "dateUpdated": "2026-08-23T12:46:02.309Z",
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    "redhat_vex": {
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      "cve": "CVE-2026-68166",
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      "status": "final",
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      "version": "3"
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      "cve": "CVE-2026-68166",
      "id": "CVE-2026-68166",
      "initial_release_date": "2026-08-13T16:23:53Z",
      "product_status:first_fixed": "65",
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      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-68166",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-68166.json",
      "version": "4"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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